<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>7.1</title>
	<script src="js/vue.js"></script>
	</head>
	<style>
		.active{ text-decoration: underline;}
		.text-danger {font-weight: bold;}
	</style>
	<body>
		<div id="app">
			<div v-bind:class="{active:isActive,'text-danger':hasError}">Hello</div>
			<div v-bind:class="classObj">Vue.js</div>
		</div>
	</body>
	<script>
		var vm = new Vue({
			el: '#app',
			data: {
				isActive: true,
				hasError: true,
				classObj: {
					active: true,
					'text-danger': true
				}
			}
		})
	</script>
</html>